1 // SPDX-License-Identifier: GPL-2.0-only 2 /* Copyright (C) 2009 Red Hat, Inc. 3 * Author: Michael S. Tsirkin <mst@redhat.com> 4 * 5 * virtio-net server in host kernel. 6 */ 7 8 #include <linux/compat.h> 9 #include <linux/eventfd.h> 10 #include <linux/vhost.h> 11 #include <linux/virtio_net.h> 12 #include <linux/miscdevice.h> 13 #include <linux/module.h> 14 #include <linux/moduleparam.h> 15 #include <linux/mutex.h> 16 #include <linux/workqueue.h> 17 #include <linux/file.h> 18 #include <linux/slab.h> 19 #include <linux/sched/clock.h> 20 #include <linux/sched/signal.h> 21 #include <linux/vmalloc.h> 22 23 #include <linux/net.h> 24 #include <linux/if_packet.h> 25 #include <linux/if_arp.h> 26 #include <linux/if_tun.h> 27 #include <linux/if_macvlan.h> 28 #include <linux/if_tap.h> 29 #include <linux/if_vlan.h> 30 #include <linux/skb_array.h> 31 #include <linux/skbuff.h> 32 33 #include <net/sock.h> 34 #include <net/xdp.h> 35 36 #include "vhost.h" 37 38 static int experimental_zcopytx = 0; 39 module_param(experimental_zcopytx, int, 0444); 40 MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;" 41 " 1 -Enable; 0 - Disable"); 42 43 /* Max number of bytes transferred before requeueing the job. 44 * Using this limit prevents one virtqueue from starving others. */ 45 #define VHOST_NET_WEIGHT 0x80000 46 47 /* Max number of packets transferred before requeueing the job. 48 * Using this limit prevents one virtqueue from starving others with small 49 * pkts. 50 */ 51 #define VHOST_NET_PKT_WEIGHT 256 52 53 /* MAX number of TX used buffers for outstanding zerocopy */ 54 #define VHOST_MAX_PEND 128 55 #define VHOST_GOODCOPY_LEN 256 56 57 /* 58 * For transmit, used buffer len is unused; we override it to track buffer 59 * status internally; used for zerocopy tx only. 60 */ 61 /* Lower device DMA failed */ 62 #define VHOST_DMA_FAILED_LEN ((__force __virtio32)3) 63 /* Lower device DMA done */ 64 #define VHOST_DMA_DONE_LEN ((__force __virtio32)2) 65 /* Lower device DMA in progress */ 66 #define VHOST_DMA_IN_PROGRESS ((__force __virtio32)1) 67 /* Buffer unused */ 68 #define VHOST_DMA_CLEAR_LEN ((__force __virtio32)0) 69 70 #define VHOST_DMA_IS_DONE(len) ((__force u32)(len) >= (__force u32)VHOST_DMA_DONE_LEN) 71 72 enum { 73 VHOST_NET_FEATURES = VHOST_FEATURES | 74 (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) | 75 (1ULL << VIRTIO_NET_F_MRG_RXBUF) | 76 (1ULL << VIRTIO_F_ACCESS_PLATFORM) | 77 (1ULL << VIRTIO_F_RING_RESET) 78 }; 79 80 enum { 81 VHOST_NET_BACKEND_FEATURES = (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2) 82 }; 83 84 enum { 85 VHOST_NET_VQ_RX = 0, 86 VHOST_NET_VQ_TX = 1, 87 VHOST_NET_VQ_MAX = 2, 88 }; 89 90 struct vhost_net_ubuf_ref { 91 /* refcount follows semantics similar to kref: 92 * 0: object is released 93 * 1: no outstanding ubufs 94 * >1: outstanding ubufs 95 */ 96 atomic_t refcount; 97 wait_queue_head_t wait; 98 struct vhost_virtqueue *vq; 99 }; 100 101 #define VHOST_NET_BATCH 64 102 struct vhost_net_buf { 103 void **queue; 104 int tail; 105 int head; 106 }; 107 108 struct vhost_net_virtqueue { 109 struct vhost_virtqueue vq; 110 size_t vhost_hlen; 111 size_t sock_hlen; 112 /* vhost zerocopy support fields below: */ 113 /* last used idx for outstanding DMA zerocopy buffers */ 114 int upend_idx; 115 /* For TX, first used idx for DMA done zerocopy buffers 116 * For RX, number of batched heads 117 */ 118 int done_idx; 119 /* Number of XDP frames batched */ 120 int batched_xdp; 121 /* an array of userspace buffers info */ 122 struct ubuf_info_msgzc *ubuf_info; 123 /* Reference counting for outstanding ubufs. 124 * Protected by vq mutex. Writers must also take device mutex. */ 125 struct vhost_net_ubuf_ref *ubufs; 126 struct ptr_ring *rx_ring; 127 struct vhost_net_buf rxq; 128 /* Batched XDP buffs */ 129 struct xdp_buff *xdp; 130 }; 131 132 struct vhost_net { 133 struct vhost_dev dev; 134 struct vhost_net_virtqueue vqs[VHOST_NET_VQ_MAX]; 135 struct vhost_poll poll[VHOST_NET_VQ_MAX]; 136 /* Number of TX recently submitted. 137 * Protected by tx vq lock. */ 138 unsigned tx_packets; 139 /* Number of times zerocopy TX recently failed. 140 * Protected by tx vq lock. */ 141 unsigned tx_zcopy_err; 142 /* Flush in progress. Protected by tx vq lock. */ 143 bool tx_flush; 144 /* Private page frag cache */ 145 struct page_frag_cache pf_cache; 146 }; 147 148 static unsigned vhost_net_zcopy_mask __read_mostly; 149 150 static void *vhost_net_buf_get_ptr(struct vhost_net_buf *rxq) 151 { 152 if (rxq->tail != rxq->head) 153 return rxq->queue[rxq->head]; 154 else 155 return NULL; 156 } 157 158 static int vhost_net_buf_get_size(struct vhost_net_buf *rxq) 159 { 160 return rxq->tail - rxq->head; 161 } 162 163 static int vhost_net_buf_is_empty(struct vhost_net_buf *rxq) 164 { 165 return rxq->tail == rxq->head; 166 } 167 168 static void *vhost_net_buf_consume(struct vhost_net_buf *rxq) 169 { 170 void *ret = vhost_net_buf_get_ptr(rxq); 171 ++rxq->head; 172 return ret; 173 } 174 175 static int vhost_net_buf_produce(struct vhost_net_virtqueue *nvq) 176 { 177 struct vhost_net_buf *rxq = &nvq->rxq; 178 179 rxq->head = 0; 180 rxq->tail = ptr_ring_consume_batched(nvq->rx_ring, rxq->queue, 181 VHOST_NET_BATCH); 182 return rxq->tail; 183 } 184 185 static void vhost_net_buf_unproduce(struct vhost_net_virtqueue *nvq) 186 { 187 struct vhost_net_buf *rxq = &nvq->rxq; 188 189 if (nvq->rx_ring && !vhost_net_buf_is_empty(rxq)) { 190 ptr_ring_unconsume(nvq->rx_ring, rxq->queue + rxq->head, 191 vhost_net_buf_get_size(rxq), 192 tun_ptr_free); 193 rxq->head = rxq->tail = 0; 194 } 195 } 196 197 static int vhost_net_buf_peek_len(void *ptr) 198 { 199 if (tun_is_xdp_frame(ptr)) { 200 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr); 201 202 return xdpf->len; 203 } 204 205 return __skb_array_len_with_tag(ptr); 206 } 207 208 static int vhost_net_buf_peek(struct vhost_net_virtqueue *nvq) 209 { 210 struct vhost_net_buf *rxq = &nvq->rxq; 211 212 if (!vhost_net_buf_is_empty(rxq)) 213 goto out; 214 215 if (!vhost_net_buf_produce(nvq)) 216 return 0; 217 218 out: 219 return vhost_net_buf_peek_len(vhost_net_buf_get_ptr(rxq)); 220 } 221 222 static void vhost_net_buf_init(struct vhost_net_buf *rxq) 223 { 224 rxq->head = rxq->tail = 0; 225 } 226 227 static void vhost_net_enable_zcopy(int vq) 228 { 229 vhost_net_zcopy_mask |= 0x1 << vq; 230 } 231 232 static struct vhost_net_ubuf_ref * 233 vhost_net_ubuf_alloc(struct vhost_virtqueue *vq, bool zcopy) 234 { 235 struct vhost_net_ubuf_ref *ubufs; 236 /* No zero copy backend? Nothing to count. */ 237 if (!zcopy) 238 return NULL; 239 ubufs = kmalloc(sizeof(*ubufs), GFP_KERNEL); 240 if (!ubufs) 241 return ERR_PTR(-ENOMEM); 242 atomic_set(&ubufs->refcount, 1); 243 init_waitqueue_head(&ubufs->wait); 244 ubufs->vq = vq; 245 return ubufs; 246 } 247 248 static int vhost_net_ubuf_put(struct vhost_net_ubuf_ref *ubufs) 249 { 250 int r = atomic_sub_return(1, &ubufs->refcount); 251 if (unlikely(!r)) 252 wake_up(&ubufs->wait); 253 return r; 254 } 255 256 static void vhost_net_ubuf_put_and_wait(struct vhost_net_ubuf_ref *ubufs) 257 { 258 vhost_net_ubuf_put(ubufs); 259 wait_event(ubufs->wait, !atomic_read(&ubufs->refcount)); 260 } 261 262 static void vhost_net_ubuf_put_wait_and_free(struct vhost_net_ubuf_ref *ubufs) 263 { 264 vhost_net_ubuf_put_and_wait(ubufs); 265 kfree(ubufs); 266 } 267 268 static void vhost_net_clear_ubuf_info(struct vhost_net *n) 269 { 270 int i; 271 272 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 273 kfree(n->vqs[i].ubuf_info); 274 n->vqs[i].ubuf_info = NULL; 275 } 276 } 277 278 static int vhost_net_set_ubuf_info(struct vhost_net *n) 279 { 280 bool zcopy; 281 int i; 282 283 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 284 zcopy = vhost_net_zcopy_mask & (0x1 << i); 285 if (!zcopy) 286 continue; 287 n->vqs[i].ubuf_info = 288 kmalloc_array(UIO_MAXIOV, 289 sizeof(*n->vqs[i].ubuf_info), 290 GFP_KERNEL); 291 if (!n->vqs[i].ubuf_info) 292 goto err; 293 } 294 return 0; 295 296 err: 297 vhost_net_clear_ubuf_info(n); 298 return -ENOMEM; 299 } 300 301 static void vhost_net_vq_reset(struct vhost_net *n) 302 { 303 int i; 304 305 vhost_net_clear_ubuf_info(n); 306 307 for (i = 0; i < VHOST_NET_VQ_MAX; i++) { 308 n->vqs[i].done_idx = 0; 309 n->vqs[i].upend_idx = 0; 310 n->vqs[i].ubufs = NULL; 311 n->vqs[i].vhost_hlen = 0; 312 n->vqs[i].sock_hlen = 0; 313 vhost_net_buf_init(&n->vqs[i].rxq); 314 } 315 316 } 317 318 static void vhost_net_tx_packet(struct vhost_net *net) 319 { 320 ++net->tx_packets; 321 if (net->tx_packets < 1024) 322 return; 323 net->tx_packets = 0; 324 net->tx_zcopy_err = 0; 325 } 326 327 static void vhost_net_tx_err(struct vhost_net *net) 328 { 329 ++net->tx_zcopy_err; 330 } 331 332 static bool vhost_net_tx_select_zcopy(struct vhost_net *net) 333 { 334 /* TX flush waits for outstanding DMAs to be done. 335 * Don't start new DMAs. 336 */ 337 return !net->tx_flush && 338 net->tx_packets / 64 >= net->tx_zcopy_err; 339 } 340 341 static bool vhost_sock_zcopy(struct socket *sock) 342 { 343 return unlikely(experimental_zcopytx) && 344 sock_flag(sock->sk, SOCK_ZEROCOPY); 345 } 346 347 static bool vhost_sock_xdp(struct socket *sock) 348 { 349 return sock_flag(sock->sk, SOCK_XDP); 350 } 351 352 /* In case of DMA done not in order in lower device driver for some reason. 353 * upend_idx is used to track end of used idx, done_idx is used to track head 354 * of used idx. Once lower device DMA done contiguously, we will signal KVM 355 * guest used idx. 356 */ 357 static void vhost_zerocopy_signal_used(struct vhost_net *net, 358 struct vhost_virtqueue *vq) 359 { 360 struct vhost_net_virtqueue *nvq = 361 container_of(vq, struct vhost_net_virtqueue, vq); 362 int i, add; 363 int j = 0; 364 365 for (i = nvq->done_idx; i != nvq->upend_idx; i = (i + 1) % UIO_MAXIOV) { 366 if (vq->heads[i].len == VHOST_DMA_FAILED_LEN) 367 vhost_net_tx_err(net); 368 if (VHOST_DMA_IS_DONE(vq->heads[i].len)) { 369 vq->heads[i].len = VHOST_DMA_CLEAR_LEN; 370 ++j; 371 } else 372 break; 373 } 374 while (j) { 375 add = min(UIO_MAXIOV - nvq->done_idx, j); 376 vhost_add_used_and_signal_n(vq->dev, vq, 377 &vq->heads[nvq->done_idx], add); 378 nvq->done_idx = (nvq->done_idx + add) % UIO_MAXIOV; 379 j -= add; 380 } 381 } 382 383 static void vhost_zerocopy_complete(struct sk_buff *skb, 384 struct ubuf_info *ubuf_base, bool success) 385 { 386 struct ubuf_info_msgzc *ubuf = uarg_to_msgzc(ubuf_base); 387 struct vhost_net_ubuf_ref *ubufs = ubuf->ctx; 388 struct vhost_virtqueue *vq = ubufs->vq; 389 int cnt; 390 391 rcu_read_lock_bh(); 392 393 /* set len to mark this desc buffers done DMA */ 394 vq->heads[ubuf->desc].len = success ? 395 VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN; 396 cnt = vhost_net_ubuf_put(ubufs); 397 398 /* 399 * Trigger polling thread if guest stopped submitting new buffers: 400 * in this case, the refcount after decrement will eventually reach 1. 401 * We also trigger polling periodically after each 16 packets 402 * (the value 16 here is more or less arbitrary, it's tuned to trigger 403 * less than 10% of times). 404 */ 405 if (cnt <= 1 || !(cnt % 16)) 406 vhost_poll_queue(&vq->poll); 407 408 rcu_read_unlock_bh(); 409 } 410 411 static const struct ubuf_info_ops vhost_ubuf_ops = { 412 .complete = vhost_zerocopy_complete, 413 }; 414 415 static inline unsigned long busy_clock(void) 416 { 417 return local_clock() >> 10; 418 } 419 420 static bool vhost_can_busy_poll(unsigned long endtime) 421 { 422 return likely(!need_resched() && !time_after(busy_clock(), endtime) && 423 !signal_pending(current)); 424 } 425 426 static void vhost_net_disable_vq(struct vhost_net *n, 427 struct vhost_virtqueue *vq) 428 { 429 struct vhost_net_virtqueue *nvq = 430 container_of(vq, struct vhost_net_virtqueue, vq); 431 struct vhost_poll *poll = n->poll + (nvq - n->vqs); 432 if (!vhost_vq_get_backend(vq)) 433 return; 434 vhost_poll_stop(poll); 435 } 436 437 static int vhost_net_enable_vq(struct vhost_net *n, 438 struct vhost_virtqueue *vq) 439 { 440 struct vhost_net_virtqueue *nvq = 441 container_of(vq, struct vhost_net_virtqueue, vq); 442 struct vhost_poll *poll = n->poll + (nvq - n->vqs); 443 struct socket *sock; 444 445 sock = vhost_vq_get_backend(vq); 446 if (!sock) 447 return 0; 448 449 return vhost_poll_start(poll, sock->file); 450 } 451 452 static void vhost_net_signal_used(struct vhost_net_virtqueue *nvq) 453 { 454 struct vhost_virtqueue *vq = &nvq->vq; 455 struct vhost_dev *dev = vq->dev; 456 457 if (!nvq->done_idx) 458 return; 459 460 vhost_add_used_and_signal_n(dev, vq, vq->heads, nvq->done_idx); 461 nvq->done_idx = 0; 462 } 463 464 static void vhost_tx_batch(struct vhost_net *net, 465 struct vhost_net_virtqueue *nvq, 466 struct socket *sock, 467 struct msghdr *msghdr) 468 { 469 struct tun_msg_ctl ctl = { 470 .type = TUN_MSG_PTR, 471 .num = nvq->batched_xdp, 472 .ptr = nvq->xdp, 473 }; 474 int i, err; 475 476 if (nvq->batched_xdp == 0) 477 goto signal_used; 478 479 msghdr->msg_control = &ctl; 480 msghdr->msg_controllen = sizeof(ctl); 481 err = sock->ops->sendmsg(sock, msghdr, 0); 482 if (unlikely(err < 0)) { 483 vq_err(&nvq->vq, "Fail to batch sending packets\n"); 484 485 /* free pages owned by XDP; since this is an unlikely error path, 486 * keep it simple and avoid more complex bulk update for the 487 * used pages 488 */ 489 for (i = 0; i < nvq->batched_xdp; ++i) 490 put_page(virt_to_head_page(nvq->xdp[i].data)); 491 nvq->batched_xdp = 0; 492 nvq->done_idx = 0; 493 return; 494 } 495 496 signal_used: 497 vhost_net_signal_used(nvq); 498 nvq->batched_xdp = 0; 499 } 500 501 static int sock_has_rx_data(struct socket *sock) 502 { 503 if (unlikely(!sock)) 504 return 0; 505 506 if (sock->ops->peek_len) 507 return sock->ops->peek_len(sock); 508 509 return skb_queue_empty(&sock->sk->sk_receive_queue); 510 } 511 512 static void vhost_net_busy_poll_try_queue(struct vhost_net *net, 513 struct vhost_virtqueue *vq) 514 { 515 if (!vhost_vq_avail_empty(&net->dev, vq)) { 516 vhost_poll_queue(&vq->poll); 517 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) { 518 vhost_disable_notify(&net->dev, vq); 519 vhost_poll_queue(&vq->poll); 520 } 521 } 522 523 static void vhost_net_busy_poll(struct vhost_net *net, 524 struct vhost_virtqueue *rvq, 525 struct vhost_virtqueue *tvq, 526 bool *busyloop_intr, 527 bool poll_rx) 528 { 529 unsigned long busyloop_timeout; 530 unsigned long endtime; 531 struct socket *sock; 532 struct vhost_virtqueue *vq = poll_rx ? tvq : rvq; 533 534 /* Try to hold the vq mutex of the paired virtqueue. We can't 535 * use mutex_lock() here since we could not guarantee a 536 * consistenet lock ordering. 537 */ 538 if (!mutex_trylock(&vq->mutex)) 539 return; 540 541 vhost_disable_notify(&net->dev, vq); 542 sock = vhost_vq_get_backend(rvq); 543 544 busyloop_timeout = poll_rx ? rvq->busyloop_timeout: 545 tvq->busyloop_timeout; 546 547 preempt_disable(); 548 endtime = busy_clock() + busyloop_timeout; 549 550 while (vhost_can_busy_poll(endtime)) { 551 if (vhost_vq_has_work(vq)) { 552 *busyloop_intr = true; 553 break; 554 } 555 556 if ((sock_has_rx_data(sock) && 557 !vhost_vq_avail_empty(&net->dev, rvq)) || 558 !vhost_vq_avail_empty(&net->dev, tvq)) 559 break; 560 561 cpu_relax(); 562 } 563 564 preempt_enable(); 565 566 if (poll_rx || sock_has_rx_data(sock)) 567 vhost_net_busy_poll_try_queue(net, vq); 568 else if (!poll_rx) /* On tx here, sock has no rx data. */ 569 vhost_enable_notify(&net->dev, rvq); 570 571 mutex_unlock(&vq->mutex); 572 } 573 574 static int vhost_net_tx_get_vq_desc(struct vhost_net *net, 575 struct vhost_net_virtqueue *tnvq, 576 unsigned int *out_num, unsigned int *in_num, 577 struct msghdr *msghdr, bool *busyloop_intr) 578 { 579 struct vhost_net_virtqueue *rnvq = &net->vqs[VHOST_NET_VQ_RX]; 580 struct vhost_virtqueue *rvq = &rnvq->vq; 581 struct vhost_virtqueue *tvq = &tnvq->vq; 582 583 int r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov), 584 out_num, in_num, NULL, NULL); 585 586 if (r == tvq->num && tvq->busyloop_timeout) { 587 /* Flush batched packets first */ 588 if (!vhost_sock_zcopy(vhost_vq_get_backend(tvq))) 589 vhost_tx_batch(net, tnvq, 590 vhost_vq_get_backend(tvq), 591 msghdr); 592 593 vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, false); 594 595 r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov), 596 out_num, in_num, NULL, NULL); 597 } 598 599 return r; 600 } 601 602 static bool vhost_exceeds_maxpend(struct vhost_net *net) 603 { 604 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 605 struct vhost_virtqueue *vq = &nvq->vq; 606 607 return (nvq->upend_idx + UIO_MAXIOV - nvq->done_idx) % UIO_MAXIOV > 608 min_t(unsigned int, VHOST_MAX_PEND, vq->num >> 2); 609 } 610 611 static size_t init_iov_iter(struct vhost_virtqueue *vq, struct iov_iter *iter, 612 size_t hdr_size, int out) 613 { 614 /* Skip header. TODO: support TSO. */ 615 size_t len = iov_length(vq->iov, out); 616 617 iov_iter_init(iter, ITER_SOURCE, vq->iov, out, len); 618 iov_iter_advance(iter, hdr_size); 619 620 return iov_iter_count(iter); 621 } 622 623 static int get_tx_bufs(struct vhost_net *net, 624 struct vhost_net_virtqueue *nvq, 625 struct msghdr *msg, 626 unsigned int *out, unsigned int *in, 627 size_t *len, bool *busyloop_intr) 628 { 629 struct vhost_virtqueue *vq = &nvq->vq; 630 int ret; 631 632 ret = vhost_net_tx_get_vq_desc(net, nvq, out, in, msg, busyloop_intr); 633 634 if (ret < 0 || ret == vq->num) 635 return ret; 636 637 if (*in) { 638 vq_err(vq, "Unexpected descriptor format for TX: out %d, int %d\n", 639 *out, *in); 640 return -EFAULT; 641 } 642 643 /* Sanity check */ 644 *len = init_iov_iter(vq, &msg->msg_iter, nvq->vhost_hlen, *out); 645 if (*len == 0) { 646 vq_err(vq, "Unexpected header len for TX: %zd expected %zd\n", 647 *len, nvq->vhost_hlen); 648 return -EFAULT; 649 } 650 651 return ret; 652 } 653 654 static bool tx_can_batch(struct vhost_virtqueue *vq, size_t total_len) 655 { 656 return total_len < VHOST_NET_WEIGHT && 657 !vhost_vq_avail_empty(vq->dev, vq); 658 } 659 660 #define VHOST_NET_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD) 661 662 static int vhost_net_build_xdp(struct vhost_net_virtqueue *nvq, 663 struct iov_iter *from) 664 { 665 struct vhost_virtqueue *vq = &nvq->vq; 666 struct vhost_net *net = container_of(vq->dev, struct vhost_net, 667 dev); 668 struct socket *sock = vhost_vq_get_backend(vq); 669 struct virtio_net_hdr *gso; 670 struct xdp_buff *xdp = &nvq->xdp[nvq->batched_xdp]; 671 size_t len = iov_iter_count(from); 672 int headroom = vhost_sock_xdp(sock) ? XDP_PACKET_HEADROOM : 0; 673 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); 674 int pad = SKB_DATA_ALIGN(VHOST_NET_RX_PAD + headroom + nvq->sock_hlen); 675 int sock_hlen = nvq->sock_hlen; 676 void *buf; 677 int copied; 678 int ret; 679 680 if (unlikely(len < nvq->sock_hlen)) 681 return -EFAULT; 682 683 if (SKB_DATA_ALIGN(len + pad) + 684 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE) 685 return -ENOSPC; 686 687 buflen += SKB_DATA_ALIGN(len + pad); 688 buf = page_frag_alloc_align(&net->pf_cache, buflen, GFP_KERNEL, 689 SMP_CACHE_BYTES); 690 if (unlikely(!buf)) 691 return -ENOMEM; 692 693 copied = copy_from_iter(buf + pad - sock_hlen, len, from); 694 if (copied != len) { 695 ret = -EFAULT; 696 goto err; 697 } 698 699 gso = buf + pad - sock_hlen; 700 701 if (!sock_hlen) 702 memset(buf, 0, pad); 703 704 if ((gso->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 705 vhost16_to_cpu(vq, gso->csum_start) + 706 vhost16_to_cpu(vq, gso->csum_offset) + 2 > 707 vhost16_to_cpu(vq, gso->hdr_len)) { 708 gso->hdr_len = cpu_to_vhost16(vq, 709 vhost16_to_cpu(vq, gso->csum_start) + 710 vhost16_to_cpu(vq, gso->csum_offset) + 2); 711 712 if (vhost16_to_cpu(vq, gso->hdr_len) > len) { 713 ret = -EINVAL; 714 goto err; 715 } 716 } 717 718 /* pad contains sock_hlen */ 719 memcpy(buf, buf + pad - sock_hlen, sock_hlen); 720 721 xdp_init_buff(xdp, buflen, NULL); 722 xdp_prepare_buff(xdp, buf, pad, len - sock_hlen, true); 723 724 ++nvq->batched_xdp; 725 726 return 0; 727 728 err: 729 page_frag_free(buf); 730 return ret; 731 } 732 733 static void handle_tx_copy(struct vhost_net *net, struct socket *sock) 734 { 735 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 736 struct vhost_virtqueue *vq = &nvq->vq; 737 unsigned out, in; 738 int head; 739 struct msghdr msg = { 740 .msg_name = NULL, 741 .msg_namelen = 0, 742 .msg_control = NULL, 743 .msg_controllen = 0, 744 .msg_flags = MSG_DONTWAIT, 745 }; 746 size_t len, total_len = 0; 747 int err; 748 int sent_pkts = 0; 749 bool sock_can_batch = (sock->sk->sk_sndbuf == INT_MAX); 750 bool busyloop_intr; 751 752 do { 753 busyloop_intr = false; 754 if (nvq->done_idx == VHOST_NET_BATCH) 755 vhost_tx_batch(net, nvq, sock, &msg); 756 757 head = get_tx_bufs(net, nvq, &msg, &out, &in, &len, 758 &busyloop_intr); 759 /* On error, stop handling until the next kick. */ 760 if (unlikely(head < 0)) 761 break; 762 /* Nothing new? Wait for eventfd to tell us they refilled. */ 763 if (head == vq->num) { 764 /* Kicks are disabled at this point, break loop and 765 * process any remaining batched packets. Queue will 766 * be re-enabled afterwards. 767 */ 768 break; 769 } 770 771 total_len += len; 772 773 /* For simplicity, TX batching is only enabled if 774 * sndbuf is unlimited. 775 */ 776 if (sock_can_batch) { 777 err = vhost_net_build_xdp(nvq, &msg.msg_iter); 778 if (!err) { 779 goto done; 780 } else if (unlikely(err != -ENOSPC)) { 781 vhost_tx_batch(net, nvq, sock, &msg); 782 vhost_discard_vq_desc(vq, 1); 783 vhost_net_enable_vq(net, vq); 784 break; 785 } 786 787 /* We can't build XDP buff, go for single 788 * packet path but let's flush batched 789 * packets. 790 */ 791 vhost_tx_batch(net, nvq, sock, &msg); 792 msg.msg_control = NULL; 793 } else { 794 if (tx_can_batch(vq, total_len)) 795 msg.msg_flags |= MSG_MORE; 796 else 797 msg.msg_flags &= ~MSG_MORE; 798 } 799 800 err = sock->ops->sendmsg(sock, &msg, len); 801 if (unlikely(err < 0)) { 802 if (err == -EAGAIN || err == -ENOMEM || err == -ENOBUFS) { 803 vhost_discard_vq_desc(vq, 1); 804 vhost_net_enable_vq(net, vq); 805 break; 806 } 807 pr_debug("Fail to send packet: err %d", err); 808 } else if (unlikely(err != len)) 809 pr_debug("Truncated TX packet: len %d != %zd\n", 810 err, len); 811 done: 812 vq->heads[nvq->done_idx].id = cpu_to_vhost32(vq, head); 813 vq->heads[nvq->done_idx].len = 0; 814 ++nvq->done_idx; 815 } while (likely(!vhost_exceeds_weight(vq, ++sent_pkts, total_len))); 816 817 /* Kicks are still disabled, dispatch any remaining batched msgs. */ 818 vhost_tx_batch(net, nvq, sock, &msg); 819 820 if (unlikely(busyloop_intr)) 821 /* If interrupted while doing busy polling, requeue the 822 * handler to be fair handle_rx as well as other tasks 823 * waiting on cpu. 824 */ 825 vhost_poll_queue(&vq->poll); 826 else 827 /* All of our work has been completed; however, before 828 * leaving the TX handler, do one last check for work, 829 * and requeue handler if necessary. If there is no work, 830 * queue will be reenabled. 831 */ 832 vhost_net_busy_poll_try_queue(net, vq); 833 } 834 835 static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock) 836 { 837 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 838 struct vhost_virtqueue *vq = &nvq->vq; 839 unsigned out, in; 840 int head; 841 struct msghdr msg = { 842 .msg_name = NULL, 843 .msg_namelen = 0, 844 .msg_control = NULL, 845 .msg_controllen = 0, 846 .msg_flags = MSG_DONTWAIT, 847 }; 848 struct tun_msg_ctl ctl; 849 size_t len, total_len = 0; 850 int err; 851 struct vhost_net_ubuf_ref *ubufs; 852 struct ubuf_info_msgzc *ubuf; 853 bool zcopy_used; 854 int sent_pkts = 0; 855 856 do { 857 bool busyloop_intr; 858 859 /* Release DMAs done buffers first */ 860 vhost_zerocopy_signal_used(net, vq); 861 862 busyloop_intr = false; 863 head = get_tx_bufs(net, nvq, &msg, &out, &in, &len, 864 &busyloop_intr); 865 /* On error, stop handling until the next kick. */ 866 if (unlikely(head < 0)) 867 break; 868 /* Nothing new? Wait for eventfd to tell us they refilled. */ 869 if (head == vq->num) { 870 if (unlikely(busyloop_intr)) { 871 vhost_poll_queue(&vq->poll); 872 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) { 873 vhost_disable_notify(&net->dev, vq); 874 continue; 875 } 876 break; 877 } 878 879 zcopy_used = len >= VHOST_GOODCOPY_LEN 880 && !vhost_exceeds_maxpend(net) 881 && vhost_net_tx_select_zcopy(net); 882 883 /* use msg_control to pass vhost zerocopy ubuf info to skb */ 884 if (zcopy_used) { 885 ubuf = nvq->ubuf_info + nvq->upend_idx; 886 vq->heads[nvq->upend_idx].id = cpu_to_vhost32(vq, head); 887 vq->heads[nvq->upend_idx].len = VHOST_DMA_IN_PROGRESS; 888 ubuf->ctx = nvq->ubufs; 889 ubuf->desc = nvq->upend_idx; 890 ubuf->ubuf.ops = &vhost_ubuf_ops; 891 ubuf->ubuf.flags = SKBFL_ZEROCOPY_FRAG; 892 refcount_set(&ubuf->ubuf.refcnt, 1); 893 msg.msg_control = &ctl; 894 ctl.type = TUN_MSG_UBUF; 895 ctl.ptr = &ubuf->ubuf; 896 msg.msg_controllen = sizeof(ctl); 897 ubufs = nvq->ubufs; 898 atomic_inc(&ubufs->refcount); 899 nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV; 900 } else { 901 msg.msg_control = NULL; 902 ubufs = NULL; 903 } 904 total_len += len; 905 if (tx_can_batch(vq, total_len) && 906 likely(!vhost_exceeds_maxpend(net))) { 907 msg.msg_flags |= MSG_MORE; 908 } else { 909 msg.msg_flags &= ~MSG_MORE; 910 } 911 912 err = sock->ops->sendmsg(sock, &msg, len); 913 if (unlikely(err < 0)) { 914 bool retry = err == -EAGAIN || err == -ENOMEM || err == -ENOBUFS; 915 916 if (zcopy_used) { 917 if (vq->heads[ubuf->desc].len == VHOST_DMA_IN_PROGRESS) 918 vhost_net_ubuf_put(ubufs); 919 if (retry) 920 nvq->upend_idx = ((unsigned)nvq->upend_idx - 1) 921 % UIO_MAXIOV; 922 else 923 vq->heads[ubuf->desc].len = VHOST_DMA_DONE_LEN; 924 } 925 if (retry) { 926 vhost_discard_vq_desc(vq, 1); 927 vhost_net_enable_vq(net, vq); 928 break; 929 } 930 pr_debug("Fail to send packet: err %d", err); 931 } else if (unlikely(err != len)) 932 pr_debug("Truncated TX packet: " 933 " len %d != %zd\n", err, len); 934 if (!zcopy_used) 935 vhost_add_used_and_signal(&net->dev, vq, head, 0); 936 else 937 vhost_zerocopy_signal_used(net, vq); 938 vhost_net_tx_packet(net); 939 } while (likely(!vhost_exceeds_weight(vq, ++sent_pkts, total_len))); 940 } 941 942 /* Expects to be always run from workqueue - which acts as 943 * read-size critical section for our kind of RCU. */ 944 static void handle_tx(struct vhost_net *net) 945 { 946 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 947 struct vhost_virtqueue *vq = &nvq->vq; 948 struct socket *sock; 949 950 mutex_lock_nested(&vq->mutex, VHOST_NET_VQ_TX); 951 sock = vhost_vq_get_backend(vq); 952 if (!sock) 953 goto out; 954 955 if (!vq_meta_prefetch(vq)) 956 goto out; 957 958 vhost_disable_notify(&net->dev, vq); 959 vhost_net_disable_vq(net, vq); 960 961 if (vhost_sock_zcopy(sock)) 962 handle_tx_zerocopy(net, sock); 963 else 964 handle_tx_copy(net, sock); 965 966 out: 967 mutex_unlock(&vq->mutex); 968 } 969 970 static int peek_head_len(struct vhost_net_virtqueue *rvq, struct sock *sk) 971 { 972 struct sk_buff *head; 973 int len = 0; 974 unsigned long flags; 975 976 if (rvq->rx_ring) 977 return vhost_net_buf_peek(rvq); 978 979 spin_lock_irqsave(&sk->sk_receive_queue.lock, flags); 980 head = skb_peek(&sk->sk_receive_queue); 981 if (likely(head)) { 982 len = head->len; 983 if (skb_vlan_tag_present(head)) 984 len += VLAN_HLEN; 985 } 986 987 spin_unlock_irqrestore(&sk->sk_receive_queue.lock, flags); 988 return len; 989 } 990 991 static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk, 992 bool *busyloop_intr) 993 { 994 struct vhost_net_virtqueue *rnvq = &net->vqs[VHOST_NET_VQ_RX]; 995 struct vhost_net_virtqueue *tnvq = &net->vqs[VHOST_NET_VQ_TX]; 996 struct vhost_virtqueue *rvq = &rnvq->vq; 997 struct vhost_virtqueue *tvq = &tnvq->vq; 998 int len = peek_head_len(rnvq, sk); 999 1000 if (!len && rvq->busyloop_timeout) { 1001 /* Flush batched heads first */ 1002 vhost_net_signal_used(rnvq); 1003 /* Both tx vq and rx socket were polled here */ 1004 vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, true); 1005 1006 len = peek_head_len(rnvq, sk); 1007 } 1008 1009 return len; 1010 } 1011 1012 /* This is a multi-buffer version of vhost_get_desc, that works if 1013 * vq has read descriptors only. 1014 * @vq - the relevant virtqueue 1015 * @datalen - data length we'll be reading 1016 * @iovcount - returned count of io vectors we fill 1017 * @log - vhost log 1018 * @log_num - log offset 1019 * @quota - headcount quota, 1 for big buffer 1020 * returns number of buffer heads allocated, negative on error 1021 */ 1022 static int get_rx_bufs(struct vhost_virtqueue *vq, 1023 struct vring_used_elem *heads, 1024 int datalen, 1025 unsigned *iovcount, 1026 struct vhost_log *log, 1027 unsigned *log_num, 1028 unsigned int quota) 1029 { 1030 unsigned int out, in; 1031 int seg = 0; 1032 int headcount = 0; 1033 unsigned d; 1034 int r, nlogs = 0; 1035 /* len is always initialized before use since we are always called with 1036 * datalen > 0. 1037 */ 1038 u32 len; 1039 1040 while (datalen > 0 && headcount < quota) { 1041 if (unlikely(seg >= UIO_MAXIOV)) { 1042 r = -ENOBUFS; 1043 goto err; 1044 } 1045 r = vhost_get_vq_desc(vq, vq->iov + seg, 1046 ARRAY_SIZE(vq->iov) - seg, &out, 1047 &in, log, log_num); 1048 if (unlikely(r < 0)) 1049 goto err; 1050 1051 d = r; 1052 if (d == vq->num) { 1053 r = 0; 1054 goto err; 1055 } 1056 if (unlikely(out || in <= 0)) { 1057 vq_err(vq, "unexpected descriptor format for RX: " 1058 "out %d, in %d\n", out, in); 1059 r = -EINVAL; 1060 goto err; 1061 } 1062 if (unlikely(log)) { 1063 nlogs += *log_num; 1064 log += *log_num; 1065 } 1066 heads[headcount].id = cpu_to_vhost32(vq, d); 1067 len = iov_length(vq->iov + seg, in); 1068 heads[headcount].len = cpu_to_vhost32(vq, len); 1069 datalen -= len; 1070 ++headcount; 1071 seg += in; 1072 } 1073 heads[headcount - 1].len = cpu_to_vhost32(vq, len + datalen); 1074 *iovcount = seg; 1075 if (unlikely(log)) 1076 *log_num = nlogs; 1077 1078 /* Detect overrun */ 1079 if (unlikely(datalen > 0)) { 1080 r = UIO_MAXIOV + 1; 1081 goto err; 1082 } 1083 return headcount; 1084 err: 1085 vhost_discard_vq_desc(vq, headcount); 1086 return r; 1087 } 1088 1089 /* Expects to be always run from workqueue - which acts as 1090 * read-size critical section for our kind of RCU. */ 1091 static void handle_rx(struct vhost_net *net) 1092 { 1093 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_RX]; 1094 struct vhost_virtqueue *vq = &nvq->vq; 1095 unsigned in, log; 1096 struct vhost_log *vq_log; 1097 struct msghdr msg = { 1098 .msg_name = NULL, 1099 .msg_namelen = 0, 1100 .msg_control = NULL, /* FIXME: get and handle RX aux data. */ 1101 .msg_controllen = 0, 1102 .msg_flags = MSG_DONTWAIT, 1103 }; 1104 struct virtio_net_hdr hdr = { 1105 .flags = 0, 1106 .gso_type = VIRTIO_NET_HDR_GSO_NONE 1107 }; 1108 size_t total_len = 0; 1109 int err, mergeable; 1110 s16 headcount; 1111 size_t vhost_hlen, sock_hlen; 1112 size_t vhost_len, sock_len; 1113 bool busyloop_intr = false; 1114 bool set_num_buffers; 1115 struct socket *sock; 1116 struct iov_iter fixup; 1117 __virtio16 num_buffers; 1118 int recv_pkts = 0; 1119 1120 mutex_lock_nested(&vq->mutex, VHOST_NET_VQ_RX); 1121 sock = vhost_vq_get_backend(vq); 1122 if (!sock) 1123 goto out; 1124 1125 if (!vq_meta_prefetch(vq)) 1126 goto out; 1127 1128 vhost_disable_notify(&net->dev, vq); 1129 vhost_net_disable_vq(net, vq); 1130 1131 vhost_hlen = nvq->vhost_hlen; 1132 sock_hlen = nvq->sock_hlen; 1133 1134 vq_log = unlikely(vhost_has_feature(vq, VHOST_F_LOG_ALL)) ? 1135 vq->log : NULL; 1136 mergeable = vhost_has_feature(vq, VIRTIO_NET_F_MRG_RXBUF); 1137 set_num_buffers = mergeable || 1138 vhost_has_feature(vq, VIRTIO_F_VERSION_1); 1139 1140 do { 1141 sock_len = vhost_net_rx_peek_head_len(net, sock->sk, 1142 &busyloop_intr); 1143 if (!sock_len) 1144 break; 1145 sock_len += sock_hlen; 1146 vhost_len = sock_len + vhost_hlen; 1147 headcount = get_rx_bufs(vq, vq->heads + nvq->done_idx, 1148 vhost_len, &in, vq_log, &log, 1149 likely(mergeable) ? UIO_MAXIOV : 1); 1150 /* On error, stop handling until the next kick. */ 1151 if (unlikely(headcount < 0)) 1152 goto out; 1153 /* OK, now we need to know about added descriptors. */ 1154 if (!headcount) { 1155 if (unlikely(busyloop_intr)) { 1156 vhost_poll_queue(&vq->poll); 1157 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) { 1158 /* They have slipped one in as we were 1159 * doing that: check again. */ 1160 vhost_disable_notify(&net->dev, vq); 1161 continue; 1162 } 1163 /* Nothing new? Wait for eventfd to tell us 1164 * they refilled. */ 1165 goto out; 1166 } 1167 busyloop_intr = false; 1168 if (nvq->rx_ring) 1169 msg.msg_control = vhost_net_buf_consume(&nvq->rxq); 1170 /* On overrun, truncate and discard */ 1171 if (unlikely(headcount > UIO_MAXIOV)) { 1172 iov_iter_init(&msg.msg_iter, ITER_DEST, vq->iov, 1, 1); 1173 err = sock->ops->recvmsg(sock, &msg, 1174 1, MSG_DONTWAIT | MSG_TRUNC); 1175 pr_debug("Discarded rx packet: len %zd\n", sock_len); 1176 continue; 1177 } 1178 /* We don't need to be notified again. */ 1179 iov_iter_init(&msg.msg_iter, ITER_DEST, vq->iov, in, vhost_len); 1180 fixup = msg.msg_iter; 1181 if (unlikely((vhost_hlen))) { 1182 /* We will supply the header ourselves 1183 * TODO: support TSO. 1184 */ 1185 iov_iter_advance(&msg.msg_iter, vhost_hlen); 1186 } 1187 err = sock->ops->recvmsg(sock, &msg, 1188 sock_len, MSG_DONTWAIT | MSG_TRUNC); 1189 /* Userspace might have consumed the packet meanwhile: 1190 * it's not supposed to do this usually, but might be hard 1191 * to prevent. Discard data we got (if any) and keep going. */ 1192 if (unlikely(err != sock_len)) { 1193 pr_debug("Discarded rx packet: " 1194 " len %d, expected %zd\n", err, sock_len); 1195 vhost_discard_vq_desc(vq, headcount); 1196 continue; 1197 } 1198 /* Supply virtio_net_hdr if VHOST_NET_F_VIRTIO_NET_HDR */ 1199 if (unlikely(vhost_hlen)) { 1200 if (copy_to_iter(&hdr, sizeof(hdr), 1201 &fixup) != sizeof(hdr)) { 1202 vq_err(vq, "Unable to write vnet_hdr " 1203 "at addr %p\n", vq->iov->iov_base); 1204 goto out; 1205 } 1206 } else { 1207 /* Header came from socket; we'll need to patch 1208 * ->num_buffers over if VIRTIO_NET_F_MRG_RXBUF 1209 */ 1210 iov_iter_advance(&fixup, sizeof(hdr)); 1211 } 1212 /* TODO: Should check and handle checksum. */ 1213 1214 num_buffers = cpu_to_vhost16(vq, headcount); 1215 if (likely(set_num_buffers) && 1216 copy_to_iter(&num_buffers, sizeof num_buffers, 1217 &fixup) != sizeof num_buffers) { 1218 vq_err(vq, "Failed num_buffers write"); 1219 vhost_discard_vq_desc(vq, headcount); 1220 goto out; 1221 } 1222 nvq->done_idx += headcount; 1223 if (nvq->done_idx > VHOST_NET_BATCH) 1224 vhost_net_signal_used(nvq); 1225 if (unlikely(vq_log)) 1226 vhost_log_write(vq, vq_log, log, vhost_len, 1227 vq->iov, in); 1228 total_len += vhost_len; 1229 } while (likely(!vhost_exceeds_weight(vq, ++recv_pkts, total_len))); 1230 1231 if (unlikely(busyloop_intr)) 1232 vhost_poll_queue(&vq->poll); 1233 else if (!sock_len) 1234 vhost_net_enable_vq(net, vq); 1235 out: 1236 vhost_net_signal_used(nvq); 1237 mutex_unlock(&vq->mutex); 1238 } 1239 1240 static void handle_tx_kick(struct vhost_work *work) 1241 { 1242 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 1243 poll.work); 1244 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); 1245 1246 handle_tx(net); 1247 } 1248 1249 static void handle_rx_kick(struct vhost_work *work) 1250 { 1251 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 1252 poll.work); 1253 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); 1254 1255 handle_rx(net); 1256 } 1257 1258 static void handle_tx_net(struct vhost_work *work) 1259 { 1260 struct vhost_net *net = container_of(work, struct vhost_net, 1261 poll[VHOST_NET_VQ_TX].work); 1262 handle_tx(net); 1263 } 1264 1265 static void handle_rx_net(struct vhost_work *work) 1266 { 1267 struct vhost_net *net = container_of(work, struct vhost_net, 1268 poll[VHOST_NET_VQ_RX].work); 1269 handle_rx(net); 1270 } 1271 1272 static int vhost_net_open(struct inode *inode, struct file *f) 1273 { 1274 struct vhost_net *n; 1275 struct vhost_dev *dev; 1276 struct vhost_virtqueue **vqs; 1277 void **queue; 1278 struct xdp_buff *xdp; 1279 int i; 1280 1281 n = kvmalloc(sizeof *n, GFP_KERNEL | __GFP_RETRY_MAYFAIL); 1282 if (!n) 1283 return -ENOMEM; 1284 vqs = kmalloc_array(VHOST_NET_VQ_MAX, sizeof(*vqs), GFP_KERNEL); 1285 if (!vqs) { 1286 kvfree(n); 1287 return -ENOMEM; 1288 } 1289 1290 queue = kmalloc_array(VHOST_NET_BATCH, sizeof(void *), 1291 GFP_KERNEL); 1292 if (!queue) { 1293 kfree(vqs); 1294 kvfree(n); 1295 return -ENOMEM; 1296 } 1297 n->vqs[VHOST_NET_VQ_RX].rxq.queue = queue; 1298 1299 xdp = kmalloc_array(VHOST_NET_BATCH, sizeof(*xdp), GFP_KERNEL); 1300 if (!xdp) { 1301 kfree(vqs); 1302 kvfree(n); 1303 kfree(queue); 1304 return -ENOMEM; 1305 } 1306 n->vqs[VHOST_NET_VQ_TX].xdp = xdp; 1307 1308 dev = &n->dev; 1309 vqs[VHOST_NET_VQ_TX] = &n->vqs[VHOST_NET_VQ_TX].vq; 1310 vqs[VHOST_NET_VQ_RX] = &n->vqs[VHOST_NET_VQ_RX].vq; 1311 n->vqs[VHOST_NET_VQ_TX].vq.handle_kick = handle_tx_kick; 1312 n->vqs[VHOST_NET_VQ_RX].vq.handle_kick = handle_rx_kick; 1313 for (i = 0; i < VHOST_NET_VQ_MAX; i++) { 1314 n->vqs[i].ubufs = NULL; 1315 n->vqs[i].ubuf_info = NULL; 1316 n->vqs[i].upend_idx = 0; 1317 n->vqs[i].done_idx = 0; 1318 n->vqs[i].batched_xdp = 0; 1319 n->vqs[i].vhost_hlen = 0; 1320 n->vqs[i].sock_hlen = 0; 1321 n->vqs[i].rx_ring = NULL; 1322 vhost_net_buf_init(&n->vqs[i].rxq); 1323 } 1324 vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX, 1325 UIO_MAXIOV + VHOST_NET_BATCH, 1326 VHOST_NET_PKT_WEIGHT, VHOST_NET_WEIGHT, true, 1327 NULL); 1328 1329 vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, EPOLLOUT, dev, 1330 vqs[VHOST_NET_VQ_TX]); 1331 vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, EPOLLIN, dev, 1332 vqs[VHOST_NET_VQ_RX]); 1333 1334 f->private_data = n; 1335 page_frag_cache_init(&n->pf_cache); 1336 1337 return 0; 1338 } 1339 1340 static struct socket *vhost_net_stop_vq(struct vhost_net *n, 1341 struct vhost_virtqueue *vq) 1342 { 1343 struct socket *sock; 1344 struct vhost_net_virtqueue *nvq = 1345 container_of(vq, struct vhost_net_virtqueue, vq); 1346 1347 mutex_lock(&vq->mutex); 1348 sock = vhost_vq_get_backend(vq); 1349 vhost_net_disable_vq(n, vq); 1350 vhost_vq_set_backend(vq, NULL); 1351 vhost_net_buf_unproduce(nvq); 1352 nvq->rx_ring = NULL; 1353 mutex_unlock(&vq->mutex); 1354 return sock; 1355 } 1356 1357 static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock, 1358 struct socket **rx_sock) 1359 { 1360 *tx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_TX].vq); 1361 *rx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_RX].vq); 1362 } 1363 1364 static void vhost_net_flush(struct vhost_net *n) 1365 { 1366 vhost_dev_flush(&n->dev); 1367 if (n->vqs[VHOST_NET_VQ_TX].ubufs) { 1368 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 1369 n->tx_flush = true; 1370 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 1371 /* Wait for all lower device DMAs done. */ 1372 vhost_net_ubuf_put_and_wait(n->vqs[VHOST_NET_VQ_TX].ubufs); 1373 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 1374 n->tx_flush = false; 1375 atomic_set(&n->vqs[VHOST_NET_VQ_TX].ubufs->refcount, 1); 1376 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 1377 } 1378 } 1379 1380 static int vhost_net_release(struct inode *inode, struct file *f) 1381 { 1382 struct vhost_net *n = f->private_data; 1383 struct socket *tx_sock; 1384 struct socket *rx_sock; 1385 1386 vhost_net_stop(n, &tx_sock, &rx_sock); 1387 vhost_net_flush(n); 1388 vhost_dev_stop(&n->dev); 1389 vhost_dev_cleanup(&n->dev); 1390 vhost_net_vq_reset(n); 1391 if (tx_sock) 1392 sockfd_put(tx_sock); 1393 if (rx_sock) 1394 sockfd_put(rx_sock); 1395 /* Make sure no callbacks are outstanding */ 1396 synchronize_rcu(); 1397 /* We do an extra flush before freeing memory, 1398 * since jobs can re-queue themselves. */ 1399 vhost_net_flush(n); 1400 kfree(n->vqs[VHOST_NET_VQ_RX].rxq.queue); 1401 kfree(n->vqs[VHOST_NET_VQ_TX].xdp); 1402 kfree(n->dev.vqs); 1403 page_frag_cache_drain(&n->pf_cache); 1404 kvfree(n); 1405 return 0; 1406 } 1407 1408 static struct socket *get_raw_socket(int fd) 1409 { 1410 int r; 1411 struct socket *sock = sockfd_lookup(fd, &r); 1412 1413 if (!sock) 1414 return ERR_PTR(-ENOTSOCK); 1415 1416 /* Parameter checking */ 1417 if (sock->sk->sk_type != SOCK_RAW) { 1418 r = -ESOCKTNOSUPPORT; 1419 goto err; 1420 } 1421 1422 if (sock->sk->sk_family != AF_PACKET) { 1423 r = -EPFNOSUPPORT; 1424 goto err; 1425 } 1426 return sock; 1427 err: 1428 sockfd_put(sock); 1429 return ERR_PTR(r); 1430 } 1431 1432 static struct ptr_ring *get_tap_ptr_ring(struct file *file) 1433 { 1434 struct ptr_ring *ring; 1435 ring = tun_get_tx_ring(file); 1436 if (!IS_ERR(ring)) 1437 goto out; 1438 ring = tap_get_ptr_ring(file); 1439 if (!IS_ERR(ring)) 1440 goto out; 1441 ring = NULL; 1442 out: 1443 return ring; 1444 } 1445 1446 static struct socket *get_tap_socket(int fd) 1447 { 1448 struct file *file = fget(fd); 1449 struct socket *sock; 1450 1451 if (!file) 1452 return ERR_PTR(-EBADF); 1453 sock = tun_get_socket(file); 1454 if (!IS_ERR(sock)) 1455 return sock; 1456 sock = tap_get_socket(file); 1457 if (IS_ERR(sock)) 1458 fput(file); 1459 return sock; 1460 } 1461 1462 static struct socket *get_socket(int fd) 1463 { 1464 struct socket *sock; 1465 1466 /* special case to disable backend */ 1467 if (fd == -1) 1468 return NULL; 1469 sock = get_raw_socket(fd); 1470 if (!IS_ERR(sock)) 1471 return sock; 1472 sock = get_tap_socket(fd); 1473 if (!IS_ERR(sock)) 1474 return sock; 1475 return ERR_PTR(-ENOTSOCK); 1476 } 1477 1478 static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd) 1479 { 1480 struct socket *sock, *oldsock; 1481 struct vhost_virtqueue *vq; 1482 struct vhost_net_virtqueue *nvq; 1483 struct vhost_net_ubuf_ref *ubufs, *oldubufs = NULL; 1484 int r; 1485 1486 mutex_lock(&n->dev.mutex); 1487 r = vhost_dev_check_owner(&n->dev); 1488 if (r) 1489 goto err; 1490 1491 if (index >= VHOST_NET_VQ_MAX) { 1492 r = -ENOBUFS; 1493 goto err; 1494 } 1495 vq = &n->vqs[index].vq; 1496 nvq = &n->vqs[index]; 1497 mutex_lock(&vq->mutex); 1498 1499 if (fd == -1) 1500 vhost_clear_msg(&n->dev); 1501 1502 /* Verify that ring has been setup correctly. */ 1503 if (!vhost_vq_access_ok(vq)) { 1504 r = -EFAULT; 1505 goto err_vq; 1506 } 1507 sock = get_socket(fd); 1508 if (IS_ERR(sock)) { 1509 r = PTR_ERR(sock); 1510 goto err_vq; 1511 } 1512 1513 /* start polling new socket */ 1514 oldsock = vhost_vq_get_backend(vq); 1515 if (sock != oldsock) { 1516 ubufs = vhost_net_ubuf_alloc(vq, 1517 sock && vhost_sock_zcopy(sock)); 1518 if (IS_ERR(ubufs)) { 1519 r = PTR_ERR(ubufs); 1520 goto err_ubufs; 1521 } 1522 1523 vhost_net_disable_vq(n, vq); 1524 vhost_vq_set_backend(vq, sock); 1525 vhost_net_buf_unproduce(nvq); 1526 r = vhost_vq_init_access(vq); 1527 if (r) 1528 goto err_used; 1529 r = vhost_net_enable_vq(n, vq); 1530 if (r) 1531 goto err_used; 1532 if (index == VHOST_NET_VQ_RX) { 1533 if (sock) 1534 nvq->rx_ring = get_tap_ptr_ring(sock->file); 1535 else 1536 nvq->rx_ring = NULL; 1537 } 1538 1539 oldubufs = nvq->ubufs; 1540 nvq->ubufs = ubufs; 1541 1542 n->tx_packets = 0; 1543 n->tx_zcopy_err = 0; 1544 n->tx_flush = false; 1545 } 1546 1547 mutex_unlock(&vq->mutex); 1548 1549 if (oldubufs) { 1550 vhost_net_ubuf_put_wait_and_free(oldubufs); 1551 mutex_lock(&vq->mutex); 1552 vhost_zerocopy_signal_used(n, vq); 1553 mutex_unlock(&vq->mutex); 1554 } 1555 1556 if (oldsock) { 1557 vhost_dev_flush(&n->dev); 1558 sockfd_put(oldsock); 1559 } 1560 1561 mutex_unlock(&n->dev.mutex); 1562 return 0; 1563 1564 err_used: 1565 vhost_vq_set_backend(vq, oldsock); 1566 vhost_net_enable_vq(n, vq); 1567 if (ubufs) 1568 vhost_net_ubuf_put_wait_and_free(ubufs); 1569 err_ubufs: 1570 if (sock) 1571 sockfd_put(sock); 1572 err_vq: 1573 mutex_unlock(&vq->mutex); 1574 err: 1575 mutex_unlock(&n->dev.mutex); 1576 return r; 1577 } 1578 1579 static long vhost_net_reset_owner(struct vhost_net *n) 1580 { 1581 struct socket *tx_sock = NULL; 1582 struct socket *rx_sock = NULL; 1583 long err; 1584 struct vhost_iotlb *umem; 1585 1586 mutex_lock(&n->dev.mutex); 1587 err = vhost_dev_check_owner(&n->dev); 1588 if (err) 1589 goto done; 1590 umem = vhost_dev_reset_owner_prepare(); 1591 if (!umem) { 1592 err = -ENOMEM; 1593 goto done; 1594 } 1595 vhost_net_stop(n, &tx_sock, &rx_sock); 1596 vhost_net_flush(n); 1597 vhost_dev_stop(&n->dev); 1598 vhost_dev_reset_owner(&n->dev, umem); 1599 vhost_net_vq_reset(n); 1600 done: 1601 mutex_unlock(&n->dev.mutex); 1602 if (tx_sock) 1603 sockfd_put(tx_sock); 1604 if (rx_sock) 1605 sockfd_put(rx_sock); 1606 return err; 1607 } 1608 1609 static int vhost_net_set_features(struct vhost_net *n, u64 features) 1610 { 1611 size_t vhost_hlen, sock_hlen, hdr_len; 1612 int i; 1613 1614 hdr_len = (features & ((1ULL << VIRTIO_NET_F_MRG_RXBUF) | 1615 (1ULL << VIRTIO_F_VERSION_1))) ? 1616 sizeof(struct virtio_net_hdr_mrg_rxbuf) : 1617 sizeof(struct virtio_net_hdr); 1618 if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) { 1619 /* vhost provides vnet_hdr */ 1620 vhost_hlen = hdr_len; 1621 sock_hlen = 0; 1622 } else { 1623 /* socket provides vnet_hdr */ 1624 vhost_hlen = 0; 1625 sock_hlen = hdr_len; 1626 } 1627 mutex_lock(&n->dev.mutex); 1628 if ((features & (1 << VHOST_F_LOG_ALL)) && 1629 !vhost_log_access_ok(&n->dev)) 1630 goto out_unlock; 1631 1632 if ((features & (1ULL << VIRTIO_F_ACCESS_PLATFORM))) { 1633 if (vhost_init_device_iotlb(&n->dev)) 1634 goto out_unlock; 1635 } 1636 1637 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 1638 mutex_lock(&n->vqs[i].vq.mutex); 1639 n->vqs[i].vq.acked_features = features; 1640 n->vqs[i].vhost_hlen = vhost_hlen; 1641 n->vqs[i].sock_hlen = sock_hlen; 1642 mutex_unlock(&n->vqs[i].vq.mutex); 1643 } 1644 mutex_unlock(&n->dev.mutex); 1645 return 0; 1646 1647 out_unlock: 1648 mutex_unlock(&n->dev.mutex); 1649 return -EFAULT; 1650 } 1651 1652 static long vhost_net_set_owner(struct vhost_net *n) 1653 { 1654 int r; 1655 1656 mutex_lock(&n->dev.mutex); 1657 if (vhost_dev_has_owner(&n->dev)) { 1658 r = -EBUSY; 1659 goto out; 1660 } 1661 r = vhost_net_set_ubuf_info(n); 1662 if (r) 1663 goto out; 1664 r = vhost_dev_set_owner(&n->dev); 1665 if (r) 1666 vhost_net_clear_ubuf_info(n); 1667 vhost_net_flush(n); 1668 out: 1669 mutex_unlock(&n->dev.mutex); 1670 return r; 1671 } 1672 1673 static long vhost_net_ioctl(struct file *f, unsigned int ioctl, 1674 unsigned long arg) 1675 { 1676 struct vhost_net *n = f->private_data; 1677 void __user *argp = (void __user *)arg; 1678 u64 __user *featurep = argp; 1679 struct vhost_vring_file backend; 1680 u64 features; 1681 int r; 1682 1683 switch (ioctl) { 1684 case VHOST_NET_SET_BACKEND: 1685 if (copy_from_user(&backend, argp, sizeof backend)) 1686 return -EFAULT; 1687 return vhost_net_set_backend(n, backend.index, backend.fd); 1688 case VHOST_GET_FEATURES: 1689 features = VHOST_NET_FEATURES; 1690 if (copy_to_user(featurep, &features, sizeof features)) 1691 return -EFAULT; 1692 return 0; 1693 case VHOST_SET_FEATURES: 1694 if (copy_from_user(&features, featurep, sizeof features)) 1695 return -EFAULT; 1696 if (features & ~VHOST_NET_FEATURES) 1697 return -EOPNOTSUPP; 1698 return vhost_net_set_features(n, features); 1699 case VHOST_GET_BACKEND_FEATURES: 1700 features = VHOST_NET_BACKEND_FEATURES; 1701 if (copy_to_user(featurep, &features, sizeof(features))) 1702 return -EFAULT; 1703 return 0; 1704 case VHOST_SET_BACKEND_FEATURES: 1705 if (copy_from_user(&features, featurep, sizeof(features))) 1706 return -EFAULT; 1707 if (features & ~VHOST_NET_BACKEND_FEATURES) 1708 return -EOPNOTSUPP; 1709 vhost_set_backend_features(&n->dev, features); 1710 return 0; 1711 case VHOST_RESET_OWNER: 1712 return vhost_net_reset_owner(n); 1713 case VHOST_SET_OWNER: 1714 return vhost_net_set_owner(n); 1715 default: 1716 mutex_lock(&n->dev.mutex); 1717 r = vhost_dev_ioctl(&n->dev, ioctl, argp); 1718 if (r == -ENOIOCTLCMD) 1719 r = vhost_vring_ioctl(&n->dev, ioctl, argp); 1720 else 1721 vhost_net_flush(n); 1722 mutex_unlock(&n->dev.mutex); 1723 return r; 1724 } 1725 } 1726 1727 static ssize_t vhost_net_chr_read_iter(struct kiocb *iocb, struct iov_iter *to) 1728 { 1729 struct file *file = iocb->ki_filp; 1730 struct vhost_net *n = file->private_data; 1731 struct vhost_dev *dev = &n->dev; 1732 int noblock = file->f_flags & O_NONBLOCK; 1733 1734 return vhost_chr_read_iter(dev, to, noblock); 1735 } 1736 1737 static ssize_t vhost_net_chr_write_iter(struct kiocb *iocb, 1738 struct iov_iter *from) 1739 { 1740 struct file *file = iocb->ki_filp; 1741 struct vhost_net *n = file->private_data; 1742 struct vhost_dev *dev = &n->dev; 1743 1744 return vhost_chr_write_iter(dev, from); 1745 } 1746 1747 static __poll_t vhost_net_chr_poll(struct file *file, poll_table *wait) 1748 { 1749 struct vhost_net *n = file->private_data; 1750 struct vhost_dev *dev = &n->dev; 1751 1752 return vhost_chr_poll(file, dev, wait); 1753 } 1754 1755 static const struct file_operations vhost_net_fops = { 1756 .owner = THIS_MODULE, 1757 .release = vhost_net_release, 1758 .read_iter = vhost_net_chr_read_iter, 1759 .write_iter = vhost_net_chr_write_iter, 1760 .poll = vhost_net_chr_poll, 1761 .unlocked_ioctl = vhost_net_ioctl, 1762 .compat_ioctl = compat_ptr_ioctl, 1763 .open = vhost_net_open, 1764 .llseek = noop_llseek, 1765 }; 1766 1767 static struct miscdevice vhost_net_misc = { 1768 .minor = VHOST_NET_MINOR, 1769 .name = "vhost-net", 1770 .fops = &vhost_net_fops, 1771 }; 1772 1773 static int __init vhost_net_init(void) 1774 { 1775 if (experimental_zcopytx) 1776 vhost_net_enable_zcopy(VHOST_NET_VQ_TX); 1777 return misc_register(&vhost_net_misc); 1778 } 1779 module_init(vhost_net_init); 1780 1781 static void __exit vhost_net_exit(void) 1782 { 1783 misc_deregister(&vhost_net_misc); 1784 } 1785 module_exit(vhost_net_exit); 1786 1787 MODULE_VERSION("0.0.1"); 1788 MODULE_LICENSE("GPL v2"); 1789 MODULE_AUTHOR("Michael S. Tsirkin"); 1790 MODULE_DESCRIPTION("Host kernel accelerator for virtio net"); 1791 MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR); 1792 MODULE_ALIAS("devname:vhost-net"); 1793